BACKGROUND AND OBJECTIVES: There are still
many questions involving study designs, data analyses and samples size which
regard to the demonstration of the benefits of regional anesthesia on patients
outcome. Database analysis and data acquisition in general cost less and require
less time as compared to large randomized controlled trials. This retrospective
study compares continuous spinal anesthesia, combined spinal-epidural and single
shot spinal anesthesia for hip surgery in elderly patients during a 4-year period,
to determine possible advantages and disadvantages of the three techniques.METHODS: Anesthetic records of 100 patients receiving spinal anesthesia
(Group 1), 100 patients receiving combined spinal-epidural block (Group 2) and
100 patients receiving continuous spinal anesthesia (Group 3) over a 4-year
period were analyzed. All blockades were performed with patients in the left
lateral position. Evaluated parameters were: puncture success, highest level
of anesthesia, lower limb motor block, quality of anesthesia, need for additional
doses, failures incidence, paresthesia, post-dural puncture headache, cardiovascular
changes, mental confusion and delirium, blood transfusion and mortality.RESULTS: There were no significant differences among groups regarding
gender, age, weight and height. Group 2 patients were shorter as compared to
groups 1 and 3. Mean bupivacaine doses were: 15.30 mg in group 1, 23.68 mg in
group 2 and 10.1 mg in group 3. They showed statistical significant differences
between groups (p < 0.01). There were significant differences (p < 0.01)
in cephalad dispersion between groups 1 and 2, 1 and 3 and 2 and 3, being lower
with continuous spinal and higher with combined spinal-epidural anesthesia.
All patients presented total motor block (Bromage score = 3). There were no
significant differences in arterial hypotension, bradycardia, paresthesia and
blood transfusion. Postoperative mental confusion was observed in 19 patients,
with no difference between techniques. There was no difference in mortality
in the first postoperative week and in the first postoperative month.CONCLUSIONS: Retrospective studies usually less and demand less time
as compared to controlled studies. This retrospective study has shown that regional
anesthesia techniques are related to a low mortality rate in the first postoperative
month and to a low incidence of complications.

Femur fracture osteosynthesis and hip artroplasty
are common procedures in elderly patients. Despite some consistent data regarding
specific systems (lung, coagulation and GI tract), no single anesthetic technique
has proved to be safer in geriatric patients submitted to major orthopedic surgeries.
When compared to general anesthesia, regional anesthesia decreases mortality
in approximately 30%1. Several randomized studies have associated
regional anesthesia to a low mortality rate in 30 days 1. In addition,
regional anesthesia decreased deep vein thrombosis in 44%, pulmonary embolism
in 55%, blood transfusion in 50%, pneumonia in 39%, respiratory depression in
59%, acute myocardial infarction in 33% and renal failure in 43% 1.
So it seems that regional anesthesia has globally reduced postoperative complications
in studies with large surgical patients populations.

Subarachnoid injection of local anesthetic was
first performed in 1898 2. In a single dose, it provides a potent
blockade of fast onset, however with extension and duration difficult to estimate
since several factors regulate local anesthetics kinetics in the CSF. Continuous
spinal anesthesia was introduced in 1907 3, developed during the
40s 4,5 and clinically investigated in the 60s and 70s 6-9.
Continuous spinal anesthesia consists of introducing a catheter in the subarachnoid
space and maintaining blockade by repeated anesthetic injections. The possibility
of fractionating local anesthetics dosage along time allows a fast onset with
better blockade quality and less hemodynamic changes 10-12. Combined
spinal-epidural anesthesia is a technique in which spinal anesthesia and epidural
catheter are simultaneously used. This blockade has been used in major orthopedic
surgeries 13-15.

This retrospective study aimed at comparing these
three anesthetic techniques in major orthopedic surgeries throughout a 4-year
period to determine their possible advantages and disadvantages in elderly patients.

METHODS

Anesthetic records of 521 patients submitted
to femur osteosynthesis and total or partial hip replacement under single shot
spinal anesthesia, combined spinal-epidural block and continuous spinal anesthesia
between January 1997 and December 2000 were selected and retrospectively analyzed.

Inclusion criteria (Chart
I) were: patients aged above 60 years, not admitted to ICU, without preoperative
vesical catheter, physical status ASA I or II, submitted to surgery within the
first 24 hours after admission, with blockades performed in the left lateral
position, not receiving low molecular weight heparin, spinal or epidural opioids,
who received pre or postoperative analgesia with the 3 in 1 blockade and who,
until the fracture, had a life compatible with age and without mental confusion.
All anesthesias were performed by the authors.

No patient was premedicated. Monitoring in the
operating room consisted of continuous ECG in CM5, non-invasive blood pressure
and pulse oximetry. All patients had an upper limb vein punctured with an 18G
venous catheter and a 2 L.min-1 oxygen catheter or Hudson mask installed.
After venous puncture, patients were given intravenous midazolam (1.5 - 4.5
mg) and meperidine (10 - 30 mg). To place the patient in the blockade position
(LLP), 10 to 30 mg intravenous ketamine were injected, or 3 in 1 blockade was
performed with 40 ml of 0.25% bupivacaine. Postoperative analgesia was achieved
with 40 ml of 0.25% bupivacaine through the 3 in 1 blockade as well, and was
maintained by injections through a catheter placed in the inguinal perivascular
space.

Group 1 - Single Shot Spinal Anesthesia (Simple
Spinal)

Spinal puncture was paramedially performed at
L2-L3 or L3-L4 interspace with the
patient in the left lateral position, using 27G disposable Quincke needles (B.
Braun, Meisungen, AG), with their bevels always parallel to dural fibers. After
obtaining CSF, 15 mg of 0.5% isobaric bupivacaine were injected without barbotage,
at a rate of 1 ml.15s-1. Patients were then immediately placed in
the supine position (Table
I). In case of failure, confirmed by lack of perineal sensitivity, a new
puncture was performed and a lower dose of the same anesthetic drug was injected.

Group 2 - Combined Spinal-Epidural Block (CSEB)

With patients in the left lateral position, epidural
puncture was paramedially performed at L2-L3 or L3-L4
interspace using the loss of resistance to air technique with an adequate single
shot device (Espocan® B. Braun Meisungen AG). Then, a 27G spinal
anesthesia needle was introduced through the Tuohy needle and, after CSF return,
0.5% isobaric bupivacaine was injected in a dose depending on patients height
(Table I). Spinal needle
was then removed and an epidural catheter was inserted. In the presence of pain
or inadequate block level, 5 ml of 0.5% bupivacaine were injected through the
epidural catheter, which was removed at the end of the surgery.

Group 3 - Continuous Spinal Anesthesia (Continuous
Spinal)

Using the previously described technique 11,
the epidural puncture was paramedially performed in the left lateral position
at L2-L3 or L3-L4 interspace with
an 18G Crawford needle. After that, dura was punctured with a Spinocath®
device (B. Braun Meisungen AG) with a 27G needle and 22G catheter set. With
the patient still in the puncture position, 5 to 10 mg of 0.5% isobaric bupivacaine
were injected, depending on patients´ height, when they were immediately
placed in the supine position. In case of pain or inadequate level, 2.5 mg of
0.5% bupivacaine were injected through the spinal catheter (Table
I), which was removed at the end of surgery.

Sensory block level and motor block degree (modified
Bromage scale, 0 = no blockade and 3 = total blockade) were tested at 5 to 20-minute
intervals. Associated diseases and drugs in use were also recorded.

Sedation was obtained with fractionated midazolam
and meperidine doses.

All values are expressed in mean and SD. The
following statistical tests were used: Kruskal-Wallis, analysis of variance,
Bonferronis test and non-parametric Chi-square test, considering significant
p < 0.05.

RESULTS

Three hundred patients´ records which complied
with the inclusion criteria were studied, with 100 cases following each technique
presented in table I.
Mean bupivacaine dose was 15.30 mg in the Simple Spinal Group, 23.68 mg in the
CSEB Group and 10.10 mg in the Continuous Spinal Group, with statistical significant
differences (p < 0.01) between groups 1 and 2, 1 and 3, and 2 and 3.

Patients demographics data are shown in table
II, with no statistical differences between groups in age, weight and gender.
Group 2 patients were statistically shorter as compared to groups 1 and 3. Patients
clinical conditions and drugs in use are shown in table
III, with no significant differences between groups.

There were 3 failures in the Simple Spinal Group
with the need for a new puncture. There were also 3 failures in the CSEB group
and surgery was performed with more anesthetic being injected through the epidural
catheter. There was no failure in the Continuous Spinal group. In 20 CSEB and
15 Continuous Spinal patients, an additional dose via catheter was needed to
begin or complete the surgery. All patients were sedated with fractionated midazolam
and meperidine doses, with no need for general anesthesia complementation.

Cephalad analgesic spread is shown in table
IV, with significant differences (p < 0.01) between groups 1 and 2, 1
and 3, and 2 and 3. In the Simple Spinal group, 75% of patients showed a spread
between T10 and T8; in the CSEB group, 77% of patients
had it between T10 and T7 and in the Continuous Spinal
group, 90% of patients presented a spread between T12 and T10.
This last group showed therefore a more uniform spread of the anesthetic.

All patients had total motor block.

There were no significant differences in hypotension,
bradycardia, paresthesia and blood transfusion. Nineteen patients presented
postoperative mental confusion, with no significant difference between techniques
(Table V).

There were also no significant differences in
mortality in the first week and within 1 month after surgery.

DISCUSSION

The number of patients not studied or excluded
from the study is high. Incomplete records may result in retrospective studies
limitations 16.

This study has shown that for major orthopedic
surgeries in elderly patients, continuous spinal anesthesia has some advantages
over simple spinal or combined spinal-epidural anesthesia: less cephalad spread,
lower incidence of arterial hypotension and less local anesthetic requirement.

Femur and hip fractures are major issues for
health services. Incidence increases with age, with predominance of women due
to association to osteoporosis. In our study, this was confirmed by the 62%
presence of women in the groups.

Combined spinal-epidural and continuous spinal
anesthesia patients received a lower initial isobaric bupivacaine dose as compared
to single shot spinal anesthesia patients. Due to the presence of the catheter,
which would allow dose increment if needed. The consequence was a 20% catheter
complementation in the combined spinal-epidural block and a 15% complementation
in the continuous spinal block with no need for general anesthesia association.

Sensory block level may be easily obtained and
controlled with continuous spinal anesthesia, while a higher dose is needed
when single shot spinal anesthesia or epidural anesthesia are used. Cardiocirculatory
stability seen in all groups with the isobaric solution shows that there might
be a dissociation between sensory and sympathetic blocks. Analgesia level with
continuous spinal anesthesia remained two segments below single shot spinal
anesthesia and 4 segments below combined spinal-epidural block.

Bromage scale is a motor block qualitative but
not quantitative indicator. However, since all patients reached the highest
lower limbs motor block degree after anesthetic injection, there was no need
to correlate different degrees. An interesting advantage of all techniques for
major orthopedic surgeries is the initial anesthetic injection in the subarachnoid
space resulting in total motor block with low doses, which would be difficult
to obtain with epidural anesthesia alone.

One of the major reasons for the preference for
epidural blockade is the early and rapid hypotension caused by spinal anesthesia,
but epidural anesthesia stability is purely historical 17. In our
study, all patients received spinal local anesthetics, but the epidural additional
dose given to the spinal-epidural group resulted in a higher incidence of hypotension
as compared to other groups, with no statistical significance though. Blood
pressure stability is a problem in elderly patients, regardless to the technique
employed. However, the incidence of hypotension among our 300 patients was less
than 10%.

An important finding of this study was the low
incidence of urine retention requiring vesical catheter (3.6%). Urine retention
is caused by peripheral and central neurogenic mechanisms interfering with micturition
reflexes, including autonomic blockade, which takes three times longer to resolve
than two segments regression time 18. In our study, bladder catheterization
was needed when blockades had already disappeared in all patients. Only 11 of
them needed a vesical catheter and this is important in the partial or total
hip replacement context. Post-arthroplasty infection results in general in prosthesis
rejection. Bacteremia may follow uretral instrumentation and the need for catheterization
increases post-arthroplasty sepsis in 6.2% 19. For providing a lower
blockade level with a lower local anesthetic dose, continuous spinal anesthesia
group showed the lowest vesical catheter need requirement.

Postoperative mental confusion is a transient
situation for the elderly and its etiology is not known. Different hip fracture
studies were unable to correlate mental confusion to the anesthetic technique
employed. There are several independent factors affecting postoperative delirium,
including postoperative pain 16. Since regional anesthesia provides
a better analgesia as compared to systemic techniques, it may be advantageous
in decreasing postoperative mental confusion. Our patients received analgesia
by the 3 in 1 blockade technique administered before or after spinal block 20.
Mental confusion incidence was 6.3% and disappeared within 1 or 2 postoperative
days. Although not achieving statistical significance, mental confusion was
seen half the times with spinal anesthesia as compared to single shot spinal
anesthesia and combined spinal-epidural block.

Regional anesthesia decreases mortality in approximately
30% when compared to general anesthesia 1. Regional anesthesia is
associated to a low mortality rate within 30 days, when 75% of deaths are caused
by pulmonary embolism, infection or heart disturbances 1. A recent
study with 450 patients has shown a mortality rate of 3% within 14 postoperative
days after spinal anesthesia, compared to 7% after general anesthesia 21.
Our study has not compared mortality with general anesthesia, but has shown
that regional anesthesia had virtually the same mortality rate (3.6%). Increased
morbidity-mortality in elderly patients is explained by a decrease in patients
basic organic functions. One study found a low mortality rate (1.38%) during
the first postoperative days in patients above 65 years of age, but didn´t
correlate it to the type of surgery 22. Similarly to vesical catheter
need and arterial hypotension, mortality rates during the first week and the
first month were two times lower with continuous spinal anesthesia as compared
to single shot spinal anesthesia and combined spinal-epidural block.

Several papers have shown the benefits of regional
anesthesia when it is extended to the postoperative period 20,23.
Postoperative analgesia, however, is just one of the factors taken into account
by morbidity-mortality studies. A study performed with postoperative lumbar
plexus block (3 in 1) 20 has shown a better analgesia lasting for
a mean time of 16 hours 20, and lower need for opioids 20
and vesical catheter, which might have contributed to the low mortality rate
in one month (3.6%).

Prospective controlled studies provide more reliable
results, but to establish whether regional anesthesia has some benefit on mortality,
it would be necessary a sample size of 24,000 patients 24. In spite
of the increased use of meta-analysis combining and evaluating data from different
sources, they have some disadvantages 25. Retrospective studies in
general cost less and take less time as compared to controlled studies, but
may result in unreliable findings 26. Our study is a retrospective
evaluation and one of the first papers in Brazil correlating regional anesthesia
techniques to morbidity-mortality in elderly patients with hip fractures. Our
results have shown a low mortality rate (3.6%) in the first month and a low
complication rate with the three regional anesthesia techniques.

REFERENCES

01. Schug AS - Is Regional Anesthesia Better than General Anesthesia? em: Syllabus of the 24th Annual Meeting of the American Society of Regional Anesthesia, Philadelphia, 1999;62-64. [ Links ]